Fluid pump assembly

ABSTRACT

A fluid pump assembly is provided. The pump has a pair of units magnetically coupled to each other. The first unit contains a drive motor and a magnetic assembly. The second unit contains a magnetic assembly and a blade of a propeller/impeller for imparting movement to a fluid. As the first unit is activated by the drive motor, a magnetic flux is created which in turn rotates the magnetic assembly in the second unit, driving the blade.

CROSS-REFERENCE TO RELATED APPLICATION AND CLAIM TO PRIORITY

This application is based on Provisional Application Ser. No.61/309,133, filed on Mar. 1, 2010, the disclosure of which isincorporated herein by reference and to which priority is claimed.

FIELD OF THE INVENTION

The present invention relates to fluid pump assemblies, especially tomagnetically coupled liquid pump assemblies useful with, for example,aquariums, foot spa basins and the like.

BACKGROUND

Fluid pump assemblies come in various designs depending on theiroperating requirements and the environment in which they will be used.One type of fluid pump assembly utilizes separate first and second unitswhich are operably connected to each other by magnets. The first unit isdesigned to be placed outside of a fluid-holding container, while thesecond unit is placed inside of the container. Each unit possesses arespective magnet operatively connected to one another such that amagnetic attraction between the magnets holds the first and second unitsin place on opposite sides of the container. The first unit contains adrive motor that rotates the first unit magnet. Due to the operativeconnection between magnets, the second unit magnet rotates with thefirst unit magnet. The second unit magnet may be connected to apropeller or an impeller to impart movement to the liquid in thecontainer.

The above-described fluid pump assembly is particularly useful inaquariums and the like because the attractive forces between the magnetsallow the respective units to be held in place at any position along thewalls of the container without requiring holes to be formed in thecontainer. The magnetic attractive force also allows the fluid pumpassembly to be mounted without brackets or other mechanical mounts,thereby reducing the overall weight of the assembly. Further, the fluidpump assembly may be located at any location on the container, such asin close proximity to an electrical outlet for powering the drive motor.The above-described magnetic coupling also eliminates the need tosubmerge electrical components in water, thus making hermetic sealsabout the motor housing unnecessary.

SUMMARY

In accordance with a first aspect of the invention, a magneticallydriven unit of a fluid pump assembly is provided. The driven unitfeatures a housing including a base and a nozzle extending from thebase. A rotator is at least partially contained in the housing. Therotator includes a magnet constructed and arranged to be magneticallycoupled to and rotationally driven by a magnet of a drive unit. A shaftis operatively connected to the rotator to rotate when the rotator isrotationally driven. A blade is operatively coupled with the shaft tomove with the rotating shaft, and a magnet cover cooperates with thehousing to enclose the rotator.

In accordance with a second aspect of the invention, a magneticallydriven unit of a fluid pump assembly is provided. The magneticallydriven unit features a housing including a base and a nozzle extendingfrom the base, and a rotator at least partially contained in thehousing. The rotator includes a magnet constructed and arranged to bemagnetically coupled to and rotationally driven by a magnet of a driveunit. The driven unit further includes a shaft operatively connected tothe rotator to rotate when the rotator is rotationally driven, a bladeoperatively coupled with the shaft to move with the rotating shaft, andan axle operably associated with the shaft, wherein the bottom of theaxle comprises a flanged base.

In accordance with additional aspects of the invention, fluid pumpassemblys featuring drive units and driven units are provided.

Other aspects of the invention, including assemblies, subassemblies,drive units, driven units, apparatus, systems, kits, methods, and thelike which constitute part of the invention, will become more apparentupon reading the following detailed description of the exemplaryembodiments and viewing the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are incorporated in and constitute a part ofthe specification. The drawings, together with the general descriptiongiven above and the detailed description of the exemplary embodimentsand methods given below, serve to explain the principles of theinvention. In such drawings:

FIG. 1 is a schematic sectional view of a pump assembly in operation inrelationship to a fluid-filled container in accordance with an exemplaryembodiment of the invention.

FIG. 2 is a perspective cut-away view of a wet-side unit of the fluidpump assembly of FIG. 1.

FIG. 3 is a perspective cut-away view of an exemplary base of thewet-side unit of FIG. 2.

FIG. 4 is a side view of the base of FIG. 3.

FIG. 5 is a perspective cut-away view of an exemplary nozzle of thewet-side unit of FIG. 2.

FIG. 6 is a side sectional view of an exemplary axle and rotatorassembly of the wet-side unit.

FIG. 7 is a perspective partially cut-away view of an exemplary bearingand shaft with attached blade of the axle and rotator assembly of FIG.6.

FIG. 8A is an upper perspective, cut-away view of an exemplary lowerbearing of the rotator assembly of FIG. 6.

FIG. 8B is a lower perspective, cut-away view of an exemplary lowerbearing of the rotator assembly.

FIG. 9 is a perspective cut-away view of an exemplary axle of the axleand rotator assembly of FIG. 6.

FIG. 10 is a perspective cut-away view of an exemplary magnet cover ofthe wet-side unit of FIG. 2.

FIG. 11 is a perspective cut-away view of an exemplary magnet cover andbase of the wet-side unit of FIG. 2.

FIG. 12 is a perspective cut-away view of an exemplary magnet cover,base, and magnet assembly.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT(S) AND EXEMPLARY METHOD(S)

Reference will now be made in detail to exemplary embodiments andmethods of the invention as illustrated in the accompanying drawings, inwhich like reference characters designate like or corresponding partsthroughout the drawings. It should be noted, however, that the inventionin its broader aspects is not limited to the specific details,representative devices and methods, and illustrative examples shown anddescribed in connection with the exemplary embodiments and methods.

As best shown in FIG. 1, an exemplary fluid pump assembly is shown inoperation in relationship to a container 26 filled with a fluid such aswater. The fluid pump assembly includes a dry-side unit or drive unit 10containing a dry-side magnet 12 outside of the container 26, and awet-side unit or driven unit 14 containing a wet-side magnet 16 insideof the container 26. The wet-side magnet 16 is operatively associatedwith a blade 20 for imparting movement to the fluid in the container 26.The dry-side magnet 12 is connected to a drive shaft 24 that is drivenby a motor 18. In an exemplary embodiment, the dry-side magnet 12 is acircular disc having at least one pair of magnetic poles N and S. Themagnetic poles may be arrayed radially about the disc, with the polesarranged in an equal and opposite fashion. The dry-side magnet 12 may bemade from a variety of magnetic materials, including neodymium or otherhigh performance magnetic materials.

The drive motor 18 may be electric, hydraulic, pneumatic, etc. In anexemplary embodiment, the drive motor 18 is an AC or DC powered electricmotor connectable to an electrical outlet or battery. The motor 18 isrotationally connected to the drive shaft 24 on which the dry-sidemagnet 12 is mounted or connected. Operation of the motor 18 rotates thedrive shaft 24, which in turn rotates the dry-side magnet 12 about thedrive shaft axis to create magnetic flux. Optionally, the motor 18 maybe shielded with a cover (discussed below) to prevent the magnetic fluxfrom adversely affecting the motor 18 and to reduce motor noise. Thecover may be made out of, for example, steel or other suitable shieldingmaterials.

The dry-side or drive unit 10 may be permanently or releasable securedto the wall of the container 26. Alternatively, the dry-side unit 10 andthe wet-side unit 14 are placed on opposite sides of the container 26,and the magnetic attraction between the respective magnets 12, 16retains the units 10, 14 in place, optionally without any mechanicalmounts or adhesive. When the fluid pump assembly is activated, the drivemotor 18 rotates the dry-side magnet 12, which causes the wet-sidemagnet 16 and blade 20 to rotate. In operation, the rotational movementof the blade 20 imparts movement to the liquid in the container 26.

The magnetic attraction between the magnets 12, 16 should besufficiently strong to hold the units 10, 14 in place in operation, thatis, so that circulation of the liquid in the container 26 and incidentalcontact do not cause the units 10, 14 to dislodge. For example, the netmagnetic attraction between the dry-side unit 10 and the wet-side unit14 may be at least 1.0 pound. The attractive force may be greater orsmaller, as needed depending on factors such as pump size, liquidviscosity, and operating environment.

FIG. 2 depicts an exemplary wet-side unit 14. As shown, the wet-sideunit or driven unit 14 includes a base 28 and a nozzle 32 combining toform a housing, a rotator assembly 30 containing at least one magnetassembly 35, and an axle 34. These components are described in furtherdetail below.

As best shown in FIG. 3, the base 28 has an inner region 36, an outerregion 38, and a side wall 40. The side wall 40 separates the innerregion 36 and the outer region 38. The side wall 40 may be formedintegrally as a single piece with the inner region 36 and the outerregion 38. Alternatively, the inner region 36, outer region 38, and/orside wall 40 may be formed separately and attached to on another. Theinner region 38 and the side wall 40 combine to house the magnetassembly 35 as shown in FIG. 2. In an exemplary embodiment, the sidewall 40 has slots 45 for retaining a magnet cover 94 described below.

As best shown in FIGS. 2 and 3, the inner region 36 has a seat 42 forretaining a thrust washer 43 (FIG. 2). The thrust washer 43 distributesthe axial load of the rotator assembly 30 and prevents force created bythe weight and movement of the rotator assembly 30 from acting directlyon the base 28. The thrust washer 43 may be made of a variety ofmaterials, including ceramic, metallic, and/or elastomeric materials. Inan exemplary embodiment, a ceramic material having a high qualitysurface finish is used for the thrust washer 43. Utilizing a ceramicmaterial will greatly reduce friction and wear during operation of thefluid pump assembly.

The outer region 38 has a peripheral edge 44, a channel 46, and lockinggrooves 48. The channel 46 holds an o-ring (not shown) for establishinga fluid-tight seal between the base 28 and the nozzle 32. As best shownin FIG. 4, the locking grooves 48 extend around the outer portion 38 ofthe base 28. There may be any number of locking grooves 48 associatedwith the base 28. In an exemplary embodiment, three locking grooves 48extend around the outer region 38 equidistant from each other. Asdescribed below, the nozzle 32 includes locking tabs 50 (FIG. 5) thatrotatably engage the locking grooves 48 to releasably connect the nozzle32 to the base 28. The number and spacing of the locking tabs 50 on thenozzle 32 should correspond to the number and spacing of the lockinggrooves 48.

In an exemplary embodiment, a backing member 41 is attached to thebottom of the base 28, that is, on an opposite surface of the base 28relative to the side wall 40. The backing member 41 may be constructedof a material and/or structure that reduce rotational and translationalmovement during operation of the fluid pump assembly. The backing member41 may be made from a variety of suitable materials including anelastomer such as neoprene or any suitable type of resilient materialsuch as foam. Although not shown, the backing member 41 may bestructured as a plurality of separate elements, such as projections,formed integrally with or separately attached to the base 28. Theprojections may correspond with similar sized and placed depressions inthe wall of the container 26 to further resist displacement of thewet-side unit 14.

As best shown in FIG. 2, the nozzle 32 connects to the base 28 asdescribed above to form the housing of the wet-side unit 14. The nozzle32 surrounds the axle 34 and the rotator assembly 30. The nozzle 32 mayserve as a protective cage to keep blade 20 from contacting anything,apart from the liquid, inside of the container 26 in which the wet-sideunit 14 is placed. As best shown in FIG. 5, the nozzle 32 may have abase section 54, an end section 56, and a central section 52 extendingbetween the base section 54 and the end section 56. In an exemplaryembodiment, the central section 52, base section 54, and end section 56are integrally formed as a single monolithic piece, though the sections52, 54, 56 may be formed separately and connected together.Additionally, one or more of the sections 52, 54, 56 may be releasablyconnected to one another so that they may be changed by a user dependingon the desired operation. The nozzle 32 may be made from a polymericmaterial and formed through a modeling process, though other suitablematerials and methods of manufacture will be understood by those ofordinary skill in the art.

The locking tabs 50 of the base section 54 may be engaged with thelocking grooves 48 to facilitate the connection between the nozzle 32and the base 28, as discussed above. The central section 52 forms thebody of the nozzle 32 and may take the form of a series of ribs 58. Theribs 58 extend longitudinally along the nozzle 32 and create slots oropenings. The ribs 58 may also be tilted or angled to direct the flow ofthe fluid through the openings. Accordingly, the ribs 58 can be designedand arranged to influence flow and turbulence, reduce d noise, andaffect efficiency of the fluid pump assembly.

Depending on the application of the fluid pump assembly, the end section56 may have a number of different designs. As best shown in FIG. 5, theend section 56 has a top wall 62 and a series of arms 64 projecting fromthe top wall 62 to a central hub 66. In an exemplary embodiment, theopenings between the ribs 58 act as liquid intake areas and the openingsbetween the arms 64 act as liquid output areas. These arms 64 may becurved and twisted as shown in FIG. 5 to impart a specific flow to thefluid leaving the nozzle 32. As with the ribs 58, the arms 64 can bedesigned to affect flow, noise, and efficiency of the fluid pumpassembly.

The central hub 66 may have a hollow cylindrical portion which extendstowards the base 28, forming an upper constraint 68. This upperconstraint 68 receives the top portion of the axle 34, as best shown inFIG. 2, to keep the axle 34 from moving laterally and optionally topartially or wholly support the axle 34. Alternatively, the axle 34 maybe supported solely by its flanged base 84 as discussed in greaterdetail below.

The design of the end section 56 shown in FIG. 5 is particularly usefulfor use with foot spa tub to impart a specific flow of fluid to a user'sfeet. The design may be altered to make it more suitable for aquariumuse. Specifically, in the context of use with an aquarium, the spacebetween the arms 64 should be sufficiently small to prevent fish fromcoming into contact with the blade 20. Additional arms 64 may beprovided to reduce the spacing between the arms, thereby making theblade 20 inaccessible to fish while permitting the flow of fluid.

As best shown in FIG. 6, the rotator assembly 30 includes a magnetassembly 35, a blade 20 for imparting movement to the fluid in thecontainer 26, a shaft 70, an upper bearing 72, and a lower bearing 74.While multiple bearings 72, 74 are shown, a single bearing may be usedfor certain applications. In these instances, the single bearing may bean upper bearing, a lower bearing, or a continuous bearing extendingfrom about the top of the shaft 70 to about the bottom of the shaft 70.The upper bearing 72 may be made from a ceramic, such as alumina oxide,to reduce wear and provide low friction. The shaft 70 and the lowerbearing 74 connect to the magnet assembly 35. This connection may beachieved through a press fit, adhesive, molded, or other suitableconnection. In an exemplary embodiment the blades 20 may be integrallyformed with the shaft 70, for example, as a molded, monolithic singepiece. Alternatively, the blades 20 may be formed separately from andconnected or fastened to the shaft 70. The blade 20 may be either animpeller type or a propeller type depending on the application of thefluid pump assembly. Also, the specific configuration and number ofblades 20 may vary depending on the application.

The upper bearing 72 is located inside of the shaft 70, as best shown inFIGS. 6 and 7. The upper bearing 72 dampens forces imparted from theshaft 70 to the axle 34. In an exemplary embodiment the upper bearing 72is made from a polymeric material; however, other appropriate materialsmay be used. When choosing the material for the upper bearing 72, thematerial used for the axle 34 should be taken into consideration, forexample, to reduce the amount of transmitted forces and the amount offriction and wear.

The lower bearing 74 rests on the thrust washer 43 and separates themagnet assembly 35 from the base 28, allowing the magnet assembly 35 torotate relative to the base 28 without producing a large amount offriction and wear and reducing noise. The thrust washer 43 also helps toabsorb axial forces transmitted from the rotator assembly 30 through thelower bearing 74 when the pump is in operation. As best shown in FIGS.8A and 8B, the lower bearing 74 has a cylindrical shaft 76 and a lowerflange 78. The lower flange 78 may have a slot 80 formed into the base.The flanged base 78 may prevent or reduce wobble and noise that mightotherwise occur during rotation of the rotor. The lower bearing 74 maybe made from a variety of suitable materials such as a polymer materialthat has low water absorption capability, for example, polyether etherketone (PEEK).

When the fluid pump assembly is switched on, drive motor 18 rotates thedry-side magnet 12, which is magnetically coupled to the wet-side magnet16 to cause its rotation. The wet-side magnet 16 is coupled to therotator assembly 30 to cause the rotor assembly 30 to rotate around theaxle 34. As best shown in FIG. 9, the axle 34 comprises a shaft 82 and aflanged base 84. In an exemplary embodiment, a sleeve 86 covers at leasta portion of the axle shaft 82. The axle 34 extends through the base 28and connects to the nozzle 32 at the upper constraint 68, as best shownin FIG. 2. The flanged base 84 contacts the bottom of the base 28 andsupports the axle 34. In certain embodiments, the axle 34 may be solelysupported by the flanged base 84. The flanged base 84 has a number ofcut-out sections, embodied as holes 85 in FIG. 9 to assist in locatingand anchoring the axle 34 to the base 28. In an exemplary embodiment,the base 28 is formed through an injection molding procedure, such asinsert molding. The axle 34 is placed into a mold and material isinjected into the mold, forming around the axle 34. The holes 85 allowthe material to flow around and through the flanged base 84 to form asecure connection between the axle 34 and the base 28.

The flanged base 84 allows the thickness of the wet-side base 28 to bekept at a minimum, thereby increasing the effectiveness of the magneticconnection between the wet-side unit 14 and the dry-side unit 12. Italso helps to prevent unwanted lateral movement or wobble of the rotatorassembly 30. This added stability decreases noise produced by the pump.

The axle 34 may be made from a variety of materials including ceramics,polymers, and/or metals. Additionally, the sleeve 86 surrounding theaxle 34 may also be made from a variety of materials. In an exemplaryembodiment, the axle 34 is made from a metal, such as corrosionresistant stainless steel, and the sleeve 86 is made from a ceramicmaterial, such as aluminum oxide having a high surface finish, forexample, between 10 microns and 80 microns, for example 40 microns. Dueto the magnetic rotor, which may make the fluid pump assembly heavierthan conventional pumps, the surface finish of the bearings 72, 74 andthe axle 34 are important to minimizing wear. A ceramic sleeve 86 allowsfor a high quality surface finish which reduces friction. If the axle 34is entirely ceramic, however, the axle 34 might not exhibit sufficientstrength to prevent it from breaking under the forces generated duringoperation of the fluid pump assembly. On the other hand, an axle 34 madeentirely of a corrosion resistant metal, such as stainless steel ortitanium, may not be hard enough or have an appropriate surface finishto wear effectively. Therefore, combining a metal axle 34 with a ceramicsleeve 86 provides a low-friction, high-strength part. This combinationprevents failures due to wear and tear caused by the operation of thefluid pump assembly, and thus greatly extends fluid pump assembly life.

As best shown in FIG. 6, the magnet assembly 35 is connected to therotator shaft 70 and the lower bearing 74. The magnet assembly 35 sitswithin the interior region 36 of the base 28. In an exemplaryembodiment, the magnet assembly 35 comprises a magnet 88 having aplurality of poles. A magnetic shield 90 may be placed on top of themagnet 88. Surrounding the magnet 88 and the magnet shield 90 is acasing 92 which connects to the lower bearing 74 and shaft 70. Thisconnection may be achieved through a press fit, adhesive, molded, orother suitable connection.

As best shown in FIGS. 10-12, the wet-side unit 14 is provided with amagnet cover 94. The rotation of the magnet assembly 35 during operationof the fluid pump assembly creates forces that will impart unwantedmovement to the fluid, such as turbulence, liquid flow which is counterto the direction of flow from the blade 20, and/or flow through thesides of nozzle 32, all of which may reduce the output efficiency of thefluid pump assembly. By providing the magnet cover 94, flow interactionmay be eliminated or greatly reduced. The magnet cover 94 has a set oftabs 96 which correspond to the slots 45 (FIGS. 3 and 4) in the sidewall40 of the base 28. As best shown in FIG. 12, when the magnet cover 94and sidewall 40 are connected, they enclose the magnet assembly 35.Cover 94 is therefore fixed, eliminating the occurrence of turbulencethat would otherwise arise due to rotation of the magnet assembly 35.Thus, fluid flows as desired from the nozzle 32. The cover may be madefrom a polymer material or from a water resistant metal such asstainless steel.

By utilizing the various exemplary aspects discussed above, amagnetically coupled fluid pump assembly may be produced which hasgreater efficiency, better durability, and operates more quietly thanprevious pumps. The foregoing description of the exemplary embodimentsof the present invention has been presented for the purpose ofillustration. It is not intended to be exhaustive or to limit theinvention to the precise forms disclosed. Obvious modifications orvariations are possible in light of the above teachings. The embodimentsdisclosed hereinabove were chosen in order to best illustrate theprinciples of the present invention and its practical application tothereby enable those of ordinary skill in the art to best utilize theinvention in various embodiments and with various modifications as aresuited to the particular use contemplated, as long as the principlesdescribed herein are followed. Thus, changes can be made in theabove-described invention without departing from the intent and scopethereof. Moreover, features or components of one embodiment may beprovided in another embodiment. Thus, the present invention is intendedto cover all such modification and variations.

What is claimed is:
 1. A magnetically driven unit of a fluid pumpassembly, comprising: a housing comprising a base and a nozzle; arotator at least partially contained in the housing, the rotatorcomprising a magnet constructed and arranged to be magnetically coupledto and rotationally driven by a magnet of a drive unit; a shaftoperatively connected to the rotator; a blade operatively coupled withthe shaft; and a magnet cover cooperating with the base to enclose therotator.
 2. The magnetically driven unit of claim 1, further comprisingan axle concentrically surrounded by the shaft.
 3. The magneticallydriven unit of claim 2, wherein the axle comprises a flanged base. 4.The magnetically driven unit of claim 3, wherein the flanged basecontacts a surface of the base.
 5. The magnetically driven unit of claim4, further comprising a ceramic sleeve concentric with the axle andpositioned between the axle and the shaft.
 6. The magnetically drivenunit of claim 5, wherein at least a portion of the ceramic sleeve isconcentric with and surrounded by a bearing.
 7. The magnetically drivenunit of claim 3, wherein the axle comprises a metallic material.
 8. Themagnetically driven unit of claim 1, wherein the nozzle comprises aplurality of ribs spaced apart from one another to create openings forallowing fluid to flow therethrough.
 9. The magnetically driven unit ofclaim 1, further comprising a casing surrounding the magnet.
 10. Themagnetically driven unit of claim 1, further comprising a lower bearingconnected to the rotator.
 11. A fluid pump assembly, comprising: themagnetically driven unit of claim 1; and a drive unit comprising a driveunit magnet for magnetically coupling to and rotationally driving theblade of the magnetically driven unit.
 12. A magnetically driven unit ofa fluid pump assembly, comprising: a housing comprising a base and anozzle extending from the base; a rotator at least partially containedin the housing, the rotator comprising a magnet constructed and arrangedto be magnetically coupled to and rotationally driven by a magnet of adrive unit; a shaft operatively connected to the rotator; a bladeoperatively coupled with the shaft; and an axle operably associated withthe shaft, wherein the bottom of the axle comprises a flanged base. 13.The magnetically driven unit of claim 12, further comprising a sleeveconcentric with and surrounding the axle.
 14. The magnetically drivenunit of claim 13, wherein the sleeve comprises a ceramic material andthe axle comprises a metallic material.
 15. The magnetically driven unitof claim 13, wherein the shaft, the axle, and the sleeve are concentricwith one another.
 16. The magnetically driven unit of claim 12, whereinthe flanged base of the axle contacts a surface of the base.
 17. Themagnetically driven unit of claim 12, wherein the base and the nozzleare releasably connected to one another.
 18. The magnetically drivenunit of claim 13, further comprising a lower bearing concentric with andsurrounding the ceramic sleeve, wherein the lower bearing is positionedbetween the magnet and the base.
 19. The magnetically driven unit ofclaim 18, further comprising a thrust washer positioned between thelower bearing and the base.
 20. A fluid pump assembly, comprising: themagnetically driven unit of claim 12; and a drive unit comprising adrive unit magnet for magnetically coupling to and rotationally drivingthe blade of the magnetically driven unit.